<style>
/*
#chart {
  height: 100%;

  background: radial-gradient(50% 50%, #3e80bd, #07142a);
  background: -o-radial-gradient(50% 50%, #3e80bd, #07142a);
  background: -moz-radial-gradient(50% 50%, #3e80bd, #07142a);
  background: -webkit-radial-gradient(50% 50%, #3e80bd, #07142a);
}
*/
/**
 * 
 */

.node circle {
  cursor: pointer;
  fill: #fff;
  stroke: steelblue;
  stroke-width: 1.5px;
}

.node text {
  font-size: 11px;
}

path.link {
  fill: none;
  stroke: #ccc;
  stroke-width: 1.5px;
}

/**
 * 
 */
.node rect {
  cursor: move;
  shape-rendering: crispEdges;
}

.node text {
  pointer-events: none;
  text-shadow: 1px 1px 2px #fff;
  font-size: 0.8em;
  font-family: sans-serif;
}

#tooltip {
  position: absolute;
  pointer-events: none;
  font-size: 0.7em;
  font-family: sans-serif;
  padding: 3px;
  width: auto;
  height: auto;
  background-color: #F2F2F2;
  -webkit-box-shadow: 0px 0px 5px rgba(0, 0, 0, 0.4);
  -mox-box-shadow: 0px 0px 0px 5px rgba(0, 0, 0, 0.4);
  box-shadow: 0px 0px 5px rbga(0, 0, 0, 0.4);
  pointer-events: none;
}

.value {
  white-space: pre-line;
  margin: 0;
}

path {
  fill: none;
  stroke: red;
  stroke-width: 5
}
</style>
<div id="chart"></div>